cleanup __writeback_single_inode
There is no reason to for the split between __writeback_single_inode and
__sync_single_inode, the former just does a couple of checks before
tail-calling the latter. So merge the two, and while we're at it split
out the I_SYNC waiting case for data integrity writers, as it's
logically separate function. Finally rename __writeback_single_inode to
writeback_single_inode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index caf0491..c54226b 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -278,7 +278,26 @@
EXPORT_SYMBOL(sb_has_dirty_inodes);
/*
- * Write a single inode's dirty pages and inode data out to disk.
+ * Wait for writeback on an inode to complete.
+ */
+static void inode_wait_for_writeback(struct inode *inode)
+{
+ DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
+ wait_queue_head_t *wqh;
+
+ wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
+ do {
+ spin_unlock(&inode_lock);
+ __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
+ spin_lock(&inode_lock);
+ } while (inode->i_state & I_SYNC);
+}
+
+/*
+ * Write out an inode's dirty pages. Called under inode_lock. Either the
+ * caller has ref on the inode (either via __iget or via syscall against an fd)
+ * or the inode has I_WILL_FREE set (via generic_forget_inode)
+ *
* If `wait' is set, wait on the writeout.
*
* The whole writeout design is quite complex and fragile. We want to avoid
@@ -288,13 +307,38 @@
* Called under inode_lock.
*/
static int
-__sync_single_inode(struct inode *inode, struct writeback_control *wbc)
+writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
{
- unsigned dirty;
struct address_space *mapping = inode->i_mapping;
int wait = wbc->sync_mode == WB_SYNC_ALL;
+ unsigned dirty;
int ret;
+ if (!atomic_read(&inode->i_count))
+ WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
+ else
+ WARN_ON(inode->i_state & I_WILL_FREE);
+
+ if (inode->i_state & I_SYNC) {
+ /*
+ * If this inode is locked for writeback and we are not doing
+ * writeback-for-data-integrity, move it to s_more_io so that
+ * writeback can proceed with the other inodes on s_io.
+ *
+ * We'll have another go at writing back this inode when we
+ * completed a full scan of s_io.
+ */
+ if (!wait) {
+ requeue_io(inode);
+ return 0;
+ }
+
+ /*
+ * It's a data-integrity sync. We must wait.
+ */
+ inode_wait_for_writeback(inode);
+ }
+
BUG_ON(inode->i_state & I_SYNC);
/* Set I_SYNC, reset I_DIRTY */
@@ -390,50 +434,6 @@
}
/*
- * Write out an inode's dirty pages. Called under inode_lock. Either the
- * caller has ref on the inode (either via __iget or via syscall against an fd)
- * or the inode has I_WILL_FREE set (via generic_forget_inode)
- */
-static int
-__writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
-{
- wait_queue_head_t *wqh;
-
- if (!atomic_read(&inode->i_count))
- WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING)));
- else
- WARN_ON(inode->i_state & I_WILL_FREE);
-
- if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_SYNC)) {
- /*
- * We're skipping this inode because it's locked, and we're not
- * doing writeback-for-data-integrity. Move it to s_more_io so
- * that writeback can proceed with the other inodes on s_io.
- * We'll have another go at writing back this inode when we
- * completed a full scan of s_io.
- */
- requeue_io(inode);
- return 0;
- }
-
- /*
- * It's a data-integrity sync. We must wait.
- */
- if (inode->i_state & I_SYNC) {
- DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC);
-
- wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
- do {
- spin_unlock(&inode_lock);
- __wait_on_bit(wqh, &wq, inode_wait,
- TASK_UNINTERRUPTIBLE);
- spin_lock(&inode_lock);
- } while (inode->i_state & I_SYNC);
- }
- return __sync_single_inode(inode, wbc);
-}
-
-/*
* Write out a superblock's list of dirty inodes. A wait will be performed
* upon no inodes, all inodes or the final one, depending upon sync_mode.
*
@@ -526,7 +526,7 @@
BUG_ON(inode->i_state & (I_FREEING | I_CLEAR));
__iget(inode);
pages_skipped = wbc->pages_skipped;
- __writeback_single_inode(inode, wbc);
+ writeback_single_inode(inode, wbc);
if (current_is_pdflush())
writeback_release(bdi);
if (wbc->pages_skipped != pages_skipped) {
@@ -708,7 +708,7 @@
might_sleep();
spin_lock(&inode_lock);
- ret = __writeback_single_inode(inode, &wbc);
+ ret = writeback_single_inode(inode, &wbc);
spin_unlock(&inode_lock);
if (sync)
inode_sync_wait(inode);
@@ -732,7 +732,7 @@
int ret;
spin_lock(&inode_lock);
- ret = __writeback_single_inode(inode, wbc);
+ ret = writeback_single_inode(inode, wbc);
spin_unlock(&inode_lock);
return ret;
}